High temperature electrical conductivity in ZnS:Al and in CdSe:Al

• Published in: Solid state ionics Vol. 173; no. 1; pp. 83 - 87
• Main Authors: Lott, K., Nirk, T., Shinkarenko, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30-09-2004
• Subjects: Al doping; Cadmium selenide; High temperature defect equilibrium; Zinc sulphide; Cadmium selenide; 61.72.Ji; 72.80.Ey; 71.20.Nr; Zinc sulphide; Al doping; High temperature defect equilibrium
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2004.07.056

High temperature electrical conductivity (HTEC) as a function of temperature and component vapour pressure has been investigated in ZnS:Al and in CdSe:Al single crystals using a two zone resistance furnace and a vacuum sealed quartz ampoule with four tungsten or graphite electrodes. The activation energies of HTEC isobars and the slope values of HTEC isotherms in the large temperature region (500–1200 °C) and in a large component vapour pressure range were determined. The region of compensation of electrons with onefold ionized substitutional Al exists up to change with the region of self-compensation of native defects at high Cd vapour pressures in HTEC isotherms of CdSe:Al. These two electroneutrality conditions were never achieved in ZnS:Al crystals under investigation. The common feature for ZnS:Al isotherms at zinc vapour pressure and for CdSe:Al isotherms at selenium vapour pressure is the existence of self-compensation of Al defects. The equilibrium constant of the association of aluminium with cadmium vacancies in CdSe:Al was determined. The increasing role of holes appears similarly at low Zn vapour pressure values in ZnS:Al and at high selenium vapour pressure values in CdSe:Al.